Retinoblastoma

Retinoblastoma is the most common primary intraocular malignant tumor of childhood with an estimted prevalence of 1 per 18000 to 30000 live births.

Retinoblastoma affects infants and children at a very early age. The majority of patients are diagnosed before they are 2 years old. The most common clinical signs of retinoblastoma are a white reflex in the pupil (leukocoria) and strabismus (crossed eye). The tumor may be visible during a funduscopic exam (dilated eye exam) or may be identified with the aid of ultrasound, or CT scans if there is hemorrhage and inflammation not allowing the ophthalmologist to see the tumor inside the eye.

Retinoblastoma occurs in both hereditary and nonhereditary forms. This distinction has important implications for patients and their families. Approximately 40% of patients with retinoblastoma have the hereditary (or germline) form of the disease. Such patients have an 85% to 90% risk of bilateral ocular disease and a lifetime predisposition to nonocular cancers throughout the body. The children of patients with hereditary retinoblastoma are at high risk for developing retinoblastoma, since the trait is transmitted in an autosomal dominant fashion. In contrast, nonhereditary retinoblastoma is unilateral, does not predispose the patient to an increased risk of second nonocular cancers, and is not transmissable.

Unilateral retinoblastomas are usually treated with enucleation (removal of the eye), because they are often advanced by the time they are diagnosed. In bilateral cases, the eye that led to the diagnosis usually has the more advanced disease. The worse eye is often enucleated and the other eye undergoes external beam radiotherapy, cryotherapy, or other conservative modes of treatment. Every effort is made to save at least one eye.

Retinoblastomas can spread outside the eye into the orbit and other parts of the body if not diagnosed and treated in a timely fashion. If this happens, chemotherapy is used to treat the patient depending on the extent of the spread.